Improvement in sheet-metal cans



T. G. F. DOLBY. Sheet-Metal Can.

No. 221,539. Patented Nov. 11,1879.

INVENTORI UNITED STATES PATENT QFFICE.

THOMAS G. F. DOLBY, OF LONDON, ENGLAND.

IMPROVEMENT IN SHEET-METAL CANS.

Specification forming part of Letters Patent No. 221,539, dated November11, 1879; application filed September 30, 1879.

ing, that the flange upon which the cover and the interposedpacking-ring is to rest shall be perfectly level, smooth, and flush allaround, whether ,the flange be turned in or out ,i but in themanufacture of flanged tin vessels in the ordinary way the overlappingedges of the flange at the joint produces an unevenness which is fatalto success in attaining a hermetic joint.

To obviate-this defect is the purpose of my present invention, which Iwill now describe.

My object is to produce a perfectly levelsurfaced flange to receive thepacking and cover.

' To this end I formthe body of the can in the usual way and solder inthe bottom. I then either throw the edge over by means of a jenny in theusual way, and then make the top surface of the' flange smooth by meansof dies, or 1 may perform the whole operation by means ofspecially-constructed dies.

When the flange is first turned by a jenny,

I employ a flat-surfaced die for the face of the.

flange, and for the under surface of the flange a die having a recesscut in its face corresponding in width to the width of the flange, inlength to the length of the lap at the joint, and in depth to thethickness of the metal of which the flange is formed, or, perhaps,atrifle more. When these dies are forced together with the flangebetween them and the lap arranged to coincide with the recess in thedie, the extrathickness of metal on the under side of the flange at thelap is depressed into the recess in the die and the upper surface of theflange is made true and level. The seam at the flange may be thenresoldered, if necessary, and the solder smoothed down.

In the drawings which serve to illustrate my invention, Figure 1 isaside elevation of a finished vessel with an outwardly-turned flangeconstructed according to my invention. Fig. 2 is a perspective view,showing the appearance of the flange if the vessel were unrolled orflattened out. Fig. 3 is a section of a vessel having an inturned flangeconstructed according to my invention, and Fig. 4 shows the flange andbody of the vessel flattened out.

A is the body of the can, and B the flange. At 0 is shown thennderlappcd, and 0 is the overlapped, portion of the flange as depressedby the dies.

A portion of the underlap at the seam may be clipped away, if founddesirable, for the better working of the dies, and the remainder bedepressed by the dies 5 but some portion of the flange should overlap,as it makes a stronger and firmer joint.

A joint might, however, be formed by cutting away the entire overlap andbringing the edges together, so as to form a buttjoint, which could besoldered, and the flange then be made true by plain dies, as beforedescribed.

The dies herein generally described I propose to make the subject of aseparate application for a patent.

What I claim as new is As an article of manufacture, a seamed tin vesselhaving a flange turned at the top, the underlapping portion of theflange at the seam being depressed, and the overlap lying in thedepression, as shown, whereby the upper surface of the flange is madetrue and level, for the purposes specified.

In witness whereof I, the said THOMAS GEORGE FONNEREAU DOLBY,.]1&V6hereunto set my hand this 12th day of September, 1879.

Witnesses:

E. H. FOULKE, THoMAs BAIRD.

T. G. F. DOLBY.

